Increasing salt tolerance in plants by overexpression of vacuolar Na+/H+ transporters

Abstract

The invention is isolated nucleic acid molecules encoding Na+ / H+ exchanger polypeptides for extrusion of monovalent cations from the cytosol of cells to provide the cell with increased salt tolerance. Crop species transformed with the nucleic acid molecule are capable of surviving in soil with high salt levels that would normally inhibit growth of the crop species.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 155,535 filed May 24, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 271,584, filed Mar. 18, 1999, which claims priority to U.S. Patent Application Ser. Nos. 60 / 116,111, filed Jan. 15, 1999, and 60 / 078,474, filed Mar. 18, 1998, each of which is hereby incorporated in its entirety.BACKGROUND OF THE INVENTION [0002] Environmental stress due to salinity is one of the most serious factors limiting the productivity of agricultural crops, which are predominantly sensitive to the presence of high concentrations of salts in the soil. Large terrestrial areas of the world are affected by levels of salt inimical to plant growth. It is estimated that 35-45% of the 279 million hectares of land under irrigation is presently affected by salinity. This is exclusive of the regions classified as arid and desert lands, (which comprises 25% of ...

AI Technical Summary

Benefits of technology

The patent describes the identification and characterization of a system of intracellular salt management in plants. The invention includes the identification of a vacuolar Na+ / H+ antiport and the demonstration of its function in increasing salt tolerance in plants. The invention also includes the isolation of nucleic acid molecules encoding the Na+ / H+ transporters and the transformation of salt-sensitive crops overexpressing these transporters. The invention can be used to engineer salt-tolerant plants by transformation with these nucleic acid molecules. The patent also includes the use of recombinant DNA technology to create recombinant nucleic acid molecules with the ability to increase salt tolerance in plants. Overall, the invention provides a valuable tool for improving salt tolerance in plants.

Problems solved by technology

Environmental stress due to salinity is one of the most serious factors limiting the productivity of agricultural crops, which are predominantly sensitive to the presence of high concentrations of salts in the soil.

Salt impinging on agricultural soils has created instability and has frequently destroyed ancient and recent agrarian societies.

Large areas of the Indian subcontinent have been rendered unproductive through salt accumulation and poor irrigation practices.

Although there is engineering technology available to combat this problem, though drainage and supply of high quality water, these measures are extremely costly.

In most of the cases, due to the increased need for extensive agriculture, neither improved irrigation efficiency nor the installation of drainage systems is applicable.

These soils are inherently high in salt and require vast amounts of irrigation to become productive.

One of the main disadvantages of using this gene for transformation of plants is associated with the typical problems encountered in heterologous gene expression, i.e. incorrect folding of the gene product, targeting of the protein to the target membrane and regulation of the protein function.

However, enzymes extracted from these plants show high sensitivity to salt.

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